what I like about it:
EASY to refill, no zippered comparetments, its open at the top.
insulated hose with quick disconnect (mine froze a lot this winter)
insulated water pouch actually too...
front water bottle holders for perpetuem
very light, small, tight, not bulky.
lots of storage in a little package, I'd say its even smaller than my nathan, or rather less bulky and more fitting, like a 'second skin' ;)
what I don't like:
Front straps are a little tight for my american build
no easy way to store the bungees that are there to store your 'walking pole' that the Europeans use like a old-mans cane ;)
Couple issues from the 50mi race test.
Overall, great fit / feel. No chafe. No hot spots. Great function too. Super easy to re-fill at aid etc.
One bungie at the bottle pack pocket broke during the race. Simply teared away.
The other bottle back got a small hole from the sharp corner of a GU pack. To me that means the nylon is not as strong as it should be. I am writing salomon about it and will let you know what they do...
Just to update this. I've switched to wearing this one here in Boulder. Mostly, because it seems to be the envy of every trail runner in passing. So much that I had a runner from behind, sprint to catch me, stop in his tracks yesterday to ask to try it on.
That's actually a true story, but in seriousness, I'm finding this thing is growing on me, and I'm liking it a lot more now, then when I first got it. It definitely fits a lot better in back than the nathan. I'm still going to make a modification to the front to get rid of those little shitty snaps with 1 'normal' strap. And, I'm actually thinking about getting these collapsible running poles like you fancy european boys have for when I'm running up summits, so the holder system is becoming more attractive as well. (i'm looking at these: http://www.rei.com/product/813391/black-diamond-ultra-distance-z-pole-trekking-poles-pair , I just don't know how to properly size them yet)